Papers by Keyword: Fatigue Stress

Abstract: Design an e-drive transmission gear, it is very crucial, to understand the failure modes since gears should be sized correctly to withstand loads that will expect to act on the gear teeth and make sure that still be within reasonable load-carrying capacity, compact and lightweight. Fatigue failure can happen on gears under repeated loading due to fatigue such as tooth root bending and contact stress of gear. Materials used in this study were two candidate alloy steels of Cr-Mo and Cr-Mo-Ni and methods employed to design the e-drive transmission gear were by iteration through KISSsoft gear simulation software as well as AGMA of Matlab script, it approaches various parameters such as helix angle, face-width, and input torque. Investigations on safety factors of root bending and contact, stresses of contact and bending, weight, compactness, quiet and smooth functioning have been done by altering the variable design parameters. To conclude that by increasing face width and helix angle both safety factors were increased uniformly regardless of the input torque as we calculated by both approaches. Similarly, the results showed that by increasing the helix angle and face width it brings to reduce the contact and bending stresses of transmission gear. As we comparing the results, the KISSsoft values are a little higher than the analytical (AGMA) values as proven in all fatigue of safety factors versus variable gear design parameter. Based on the safety factor, compactness, lightweight and quiet for smooth function of the designed e-drive mating gears are proven as the face width is 24.5 mm and the helix angle is 25^o.

Abstract: The fatigue life and fatigue stress of 30CrMnSiA material are studied by fracture retro estimation under experimental conditions. With the help of Scanning electron microscopy (SEM), fatigue crack can be observed. By Paris law, the fatigue life and fatigue stress of 30CrMnSiA material can be estimated by fatigue striation under the experimental environment. The method is simple and feasible, and the relative error is lower.

Abstract: Some key components’ failure often occurs in the process of the use of large-scale mining coal machine, and seriously affects the production of the enterprise. So it is necessary that analysis on the failure mechanical reason of guide shoes with the coal-winning machine by the modern mechanics analysis method. The stress diagram of guide shoes could be got by static analysis with MATLAB, and the dangerous parts of the finite element model with guide shoes appeared after loading. Finally, analysis on the fatigue strength and fatigue life of components under various complex condition, which provide some reference theory basis for the future related product designing, Manufacturing and maintenance.

Abstract: Influence of diaphragm parameter on stress amplitude and fatigue damage of diaphragm details were investigated based on Tai Zhou Yangtze River Bridge. FEM of steel bridge deck and diaphragm detail were established. Boundary conditions of the diaphragm details FEM were interpolated by sub-model method, and the accurate local stresses of diaphragm details correspond to different lateral distribution of wheels were calculated. Results show the stress amplitude of diaphragm details reach maximum when wheel off-center position is 150mm, and it decreases with the increase of wheel off-center position greatly. The stress amplitude of diaphragm details increase with the increase of the distance of diaphragms, and increasing diaphragm’s thickness can improve fatigue stress of steel bridge deck.

Abstract: An efficient finite element (FE) method, multivariate quadratic regression approach, is proposed for calculating the fatigue stress spectrum of engineering structures. The calculation starts from a dynamic load history. A regression function is established as a relation from the concurrent components of structural balance force systems into the structural stress. Parameters of the relation are measured by the stress data using an elastic-plastic FE method under selected groups of balance force systems. The selected systems should cover the possible load range with a similar service condition. After passing the fit effect check, the regression equation can transfer the structural load history into the stress history at the preferred position. Application on the determination of fatigue stress spectrum for the bolster of K6 type bogie has indicated availability of the present approach. Some deficiencies have been overcome from the much time cost by transient approach and the entire elastic material relation by quasi-static approach.